Tone control arrangement with indicators



Dec. 27, 1949 R. G. MILLER ET AL 2,492,310

TONE CONTROL ARRANGEMENT WITH INDICATORS Filed June 8, 1949 FlG.l

I INVENTORS RUDOLPH G. MILLER BY GARRARD MOUNTJOY ATTORNEY Patented Dec.27, 1949 TONE CONTROL ARRANGEMENT WITH INDICATORS Rudolph G. Miller,Rochester, and Garrard Mountjoy, Canandaigua, N. Y., assignors toStromberg-Carlson Company, a corporation of New York Application June 8,1949, Serial No. 97,771

Claims. 1

Our invention relates to improvements in tone control devices used inthe electrical reproduction of sound, and more particularly tomechanical arrangements for controlling the frequency response ofamplifiers and the like.

Our invention finds greatest application in amplifiers for reproducingmusic and other entertaining and informative sounds of the type commonlyencountered in radio programs and phonograph records. The amplifiersused for this purpose usually employ electron tubes to provide therequired amplification. However, the highand low-frequency responsecharacteristics of these amplifiers may be either excessive orinsufficient for a particular program. For example, too much emphasis onthe bass notes may result in a boomy quality of voice reproduction,although it may be desirable for certain kinds of music. On the otherhand, the presence of noise in the program material may make itdesirable on some occasions to diminish the high, or treble, response ofthe amplifier. Similarly, it may be desirable to boost the high or lowfrequencies, depending upon the characteristics of the program material.

It is known to provide bass and treble tone controls for selecting thelow-and high-frequency responses of the amplifier independently of eachother. These controls are usually potentiometers. Prior to ourinvention, it was necessary to read or estimate the individual settingsof these potentiometers, in order to visualize the overall type ofresponse resulting. As is well known, the balance between bass andtreble is fully as important as the ability to augment or diminish thebass or treble responses individually. Thus, if it is desired for anyreason to mute the high frequency response, it may be advisable todiminish the low frequency response also. This balance is generallytermed tonal balance.

It is therefore an object of our invention to provide means for quicklyand easily determining the particular frequency response being obtainedin an amplifier.

It is also an object of our invention to provide an indicator of thetonal balance of an amplifier which enables tonal balance adjustments tobe easily visualized.

It is a further object of our invention to provide an indication of thetonal balance of an amplifier by means of colored light.

It is still a further object of our invention to provide a tonal balanceindicator for an amplifier 2 a depth of coloration proportional to theemphasis being placed on a particular portion of the responsecharacteristic of the amplifier, are mixed to provide an additionalcolor indicative of the tonal balance selected.

These and other objects of our invention we accomplish by associatingdistinctive reference in dicia with the bass and treble tone controls,respectively. We arrange these indicia to be seen by the operator ofthis tone control assembly in such a way that he interprets not only thesettings of the individual controls by means of the respective indicia,but can also interpret the degree of tonal balance being used by asuperposition of these indicia.

In general, we prefer to provide an arrangement in which these indiciacomprise lights of distinctive colors. In a preferred embodiment of ourinvention, explained in detail later in this specification, we provide asource of light inside a translucent cylinder. This cylinder is coupledfor rotation to one of the tone controlling means. A second cylinder isdisposed coaxially around the first cylinder, and is coupled to theother tone controlling means. Each cylinder is distinctively coloredwith a density of coloration which varies with the degree of actuationof the respective tone controlling means. The cylinders are so disposedwith respect to each other that part of the colored light distinctive toeach of the cylinders is seen by the operator of our invention. Theremaining part of the light of one cylinder is arranged to overlap theremaining part of the light of the other cylinder. In this way,distinctive coloration is produced in the overlapped area which isinterpreted by the operator as indicative of the degree of tonal balancein use. The colored areas appear to the operator of our invention asshown in Figure 2 of the accompanying drawing.

The foregoing and other objects and advantages of our invention willbecome apparent as the following description proceeds, and the featuresof novelty which characterize our invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

For a better understanding of our invention, reference may be had to theaccompanying drawing in which Fig. 1 represents a partial section alongline AA of Fig. 2, of a preferred embodiment of our invention, as viewedfrom the top, and Fig. 2 is a front view of our invention, as seen bythe user of an amplifier to which it is conin which various distinctivecolors, each having nected.

Referring now to Fig. l, which illustrates the preferred form of ourinvention, we provide a bass tone control potentiometer I, the shaft ofwhich is parallel to the front panel 2. We also provide a treble tonecontrol potentiometer 3 similarly arranged. Potentiometers l and 3 aresupported by means of brackets 4 and 5, respectively, which are fastenedto frame 6 by means of screws 1. Wires 8 from these potentiometers maybe gathered into a cable 3 leading to the chassis 33 of the amplifier.It should be understood that our invention is equally applicable to anamplifier built on an individual chassis or to an amplifier constructedon a chassis common to the other circuits, such as a radio receiver. Athumb wheel Ill, which may be knurled on its outer circumference II, issecured to the shaft of bass tone control potentiometer l by suitablefastening means, such as set screw 92. A thumb wheel I3, which may alsobe knurled on its outer circumference I4, is suitably secured to theshaft of treble tone control potentiometer 3 as by means of set screw15. Supported by thumb wheel 13 is a lamp socket l6 insulated from thumbwheel If; by means of insulator Hi. The center contact ll of socket I issecured to thumb wheel I3. The outer portion of the socket is suppliedwith electric current by wire [9 which passes through hole '20 in thumbWheel i4, passes around the shaft of treble tone control potentiometer 3and is secured to a terminal block 2 l. Terminal block 2! may besupplied with current by wire 22, which maybe included in cable 9 to theamplifier chassis. Secured by socket I6 is a lamp 23 which is lightedwhenever the amplifier is turned on.

A translucent cylinder 24 is secured to thumb wheel l3 by means of screw25. Screw 25 projects through thumb wheel it in order to provide astopping action when it strikes stop 23. (Stop 26 is indicatedschematically, since its size and location depend on the amount ofrotation required for potentiometer 3. In some cases, a stop is providedwithin the case of the potentiometer.) A second translucent cylinder 2!is secured to thumb wheel it by means of screw 28. Screw 2 8 projectsthrough thumb wheel it in order to providea stopping action when itstrikes stop 29. (Stop 29 is shown schematically for the same reason asstop 26 is.) It will be noted that the bass and treble tone controlpotentiometers are so arranged that translucent cylinder 21 is disposedwithin the translucent cylinder 24.

Secured to at least a portion of one of the surfaces, preferably theinner circumference, of translucent cylinder 23 is a strip or coating ofdistinctively colored translucent material 33. We prefer that theportion of the surface covered by strip 30 comprise about two-thirds ofthe axial length of cylinder 24. The density of coloration of strip 30is graduated smoothly in a circumferential direction, but is uniform inthe axial direction. The minimum density of strip 30 is arranged to benearest the operator at 3| (located in front of panel 2) when the trebletone control 3 is in the position to produce the maximum trebleresponse. We prefer that strip 30 be colored blue, although any colormay be used without departing from the spirit of our invention. The besteffect is produced if the color is of the group known as cool, becausehuman beings tend to associate high notes with cool colors and low noteswith Warm colors.

A translucent strip or coating 32 is secured to at least a portion ofone of the surfaces of the axial length, preferably the innercircumference,

- uniform in the axial direction.

of cylinder 2'1. We prefer that the portion of the surface covered bystrip 32 comprise about twothirds of the axial length of cylinder El,such that one third of strip 32 overlaps one third of strip 33 incylinder 24. Strip 32 is distinctively colored, i. e., strip 32 has acolor different from that of strip 30. Again. any color (other than thatused for strip 33) may be used without departing from the spirit of ourinvention, but we prefer to use a Warm color. We find that the besteffect is obtained if the color selected for strip 32 is red. Thedensity of coloration of strip 32 varies smoothly in a circumferentialdirection from minimum to maximum but is preferably The minimum densityis arranged to be nearest the operator at 3| when the bass tone controlpotentiometer is in a position to produce minimum bass response. We wishto point out here that the use of separate translucent strips 30 and 32is not necessary if corresponding axial lengths of the translucentcylinders 24 and 2'] are each distinctively colored, while the remainingportion of the axial length remains translucent and uncolorcd. If it isnot desired to give separate color indication of the positions of thebass and treble control potentiometers, the entire axial length ofcylinders 24 and 21 may be colored.

The effect of the described embodiment of our invention upon theoperator at 3| is represented in Fig. 2. Thumb wheels ID and I3 projectthrough the front panel 2 and may be easily rotated by reason of theknurling of the outer circumferences II and I4 respectively. The outersurface of the outer cylinder 25 is nearest the operator. The opera-torsees three areas of colored light, the left-hand one being red, thecenter one purple, and the right-hand one blue. The shade of red seen inthe left-hand area will depend upon the setting of the bass tone controlpotentiometer, and will be lightest if the bass response is at aminimum. The blue area will be most lightly colored if the treble tonecontrol potentiometer is set to produce maximum treble response. Thecolors of the center section will be proportional to the densities ofthe red and blue portions which are combined to form purple. In thisway, the particular shade of purple produced in the center area uniquelycorresponds to a particular combination of settings of the bass andtreble tone control potentiometers. If desired, the embodiment justdescribed may be fastened to the front panel of the cabinet in which theamplifier is housed. The front of the amplifier chassis 33 may then beplaced in contact with spring 34. A ground return for the current supplyof the lamp 33 is therefore conveniently provided. When this arrangementis used, it is not necessary to remove the tone control assembly fromthe front panel when it is desired to service the amplifier chassisalone.

We particularly wish to point out "the means by which the lamp 223 iscontinuously provided with current during and after rotation of thumbwheel [3. One or more turns of wire ['9 are wound around the shaft oftreble tone control potentiometer 3 such that the turn (or turns) isnearly tight on the shaft when the shaft is in its position of minimumrotation, and may be completely unwound in the position of maximumtravel.

While we have shown and described a specific embodiment of ourinvention, other modifications will readily occur to those skilled inthe art. For example, other translucent means may be substituted forcylinders 24 and 21. In one modification, means other than color may beemployed,

as numerals, for example. Another arrangement is to omit the overlappingdisposition of color and the attendant blended band or area. We do not,therefore, desire our invention to be limited to the specificarrangement shown and described, and .we intend in the appended claimsto cover all modifications within the spirit and scope of our invention.

What we claim is:

1. In a tone control assembly for amplifiers and the like; bass tonecontrolling means; treble tone controlling means; first translucentmeans associated with said bass tone controlling means; secondtranslucent means associated with said treble tone controlling means;each of said translucent means bearing distinctive reference indicia;means for projecting light through both translucent means; and means forvarying the relative positions of said translucent and said light meansfor changing the illuminated impression conveyed to the operator of saidtone controlling means in accordance with the relative settings of saidtone controlling means.

2. In a tone control assembly for amplifiers and the like; bass tonecontrolling means; treble tone controlling means; first translucentmeans associated with said bass tone controlling means; secondtranslucent means associated with said treble tone controlling means;each of said translucent means bearing distinctive reference indicia;said reference indicia being respectively arranged to at least partiallyoverlap; means for projecting light through both translucent means; andmeans for varying the relative positions of said translucent and saidlight means for changing the illuminated impression conveyed to theoperator of said tone controlling means in accordance with the relativesettings of said tone controlling means.

3. In a tone control assembly for amplifiers and the like; bass tonecontrolling means; treble tone controlling means; first translucentmeans associated with said bass tone controlling means; secondtranslucent means associated with said treble tone controlling means;each of said translucent means being distinctively colored, thecharacter of the coloring of each means differing across the surfacethereof; means for projecting light through both translucent means; andmeans for varying the relative positions of said translucent and saidlight means for varying the color impression conveyed to one operatingsaid tone controlling means in accordance with the various settings ofsaid tone controlling means.

4. In an amplifier, the combination of bass tone controlling means,treble tone controlling means, first translucent means disposed formovement by actuation of said treble tone controlling means, secondtranslucent means disposed for movement by actuation of said treble tonecontrolling means, each of said translucent means being distinctivelycolored, the density of the coloration varying across the surfaces ofsaid translucent means, and a source of light arranged to shine throughdifferent portions of said translucent means in tandem, as said meansare moved, whereby the color of the light emerging from said secondtranslucent means indicates the degree of tonal balance selected withsaid tone controlling means.

5. In an amplifier, the combination of bass tone controlling means,treble tone controlling means, a first translucent means coupled forrotation to said bass tone controlling means, a second translucent meanscoupled for rotation to said treble tone controlling means, each of saidtranslucent means being distinctively colored and mounted foroverlapping relationship, the density of coloration varying smoothlywith the amount of rotation of the respective one of said tonecontrolling means, and a source of light arranged to shine through theoverlapping portions of said translucent means, whereby the color of thelight emerging from the said second translucent means indicates theparticular tonal balance selected with said tone controlling means.

6. In an arrangement for selecting at will the tonal balance of anamplifier, the combination of a first translucent cylinder coaxiallydisposed within a second translucent cylinder; means for manuallyrotating said cylinders independently of each other; a source of lightdisposed within the inner one of said cylinders; bass tone control lingmeans coupled for rotation to one of said cylinders; treble tonecontrolling means coupled for rotation to the other of said cylinders;each of said cylinders having distinctive coloring means such that thedensity of coloration changes, with rotation, whereby the color of thelight emerging from the outer one of said cylinders indicates the degreeof tonal balance selected with said tone controlling means.

7. In an arrangement for selecting at will the tonal balance of anamplifier, the combination of a first translucent cylinder coaxiallydisposed within a second translucent cylinder; means for manuallyrotating said cylinders independently of each other; a source of lightdisposed within the inner one of said cylinders; bass tone controllingmeans coupled for rotation to one of said cylinders treble tonecontrolling means coupled for rotation to the other of said cylinders;each of said cylinders having distinctive coloring means such that thedensity of coloration changes, in a circumferential but not an axialdirection, with rotation, whereby the color of the light emerging fromthe outer one of said cylinders indicates the degree of tonal balanceselected with said tone controlling means.

8. In an arrangement for selecting at will the tonal balance of anamplifier, the combination of a first translucent cylinder coaxiallydisposed within a second translucent cylinder; means for manuallyrotating said cylinders independently of each other; a source of lightdisposed within the inner one of said cylinders; bass tone controllingmeans coupled for rotation to one of said cylinders; treble tonecontrolling means coupled for rotation to the other of said cylinders;each of said cylinders having distinctive coloring means such that thedensity of coloration changes with rotation, said coloring means atleast partially overlapping, whereby three colored areas are seen by theoperator of said tone controlling means, the color of the first of saidareas being indicative of the setting of said bass tone controllingmeans, the second of said areas being indicative of the setting of saidtreble tone controlling means, and the third of said areas having acolor resulting from the overlapping of said coloring means, therebyindicating the degree of tonal balance selected.

9. In an arrangement for selecting at will the tonal balance of anamplifier, the combination of a first translucent cylinder coaxiallydisposed within a second translucent cylinder; means for manuallyrotating said cylinders independently of each other; an electric sourceof light disposed within and supported by said first translucentcylinder, means for supplying electricity contimrously to said sourceduring and aftr'rotation of said first translucent means; bass tonecontrolling means coupled for rotation to the other of said cylinders;treble tone controlling means coupled for rotation to the other of saidcylinders; each of said cylinders having distinctive colorin means suchthat the density of coloration changes, in a circumferential but not anaxial direction, with rotation, whereby the color of the light emergingfrom the outer one of said cylinders is formed by passage through eachof said distinctive coloring means, and therefore uniquely indicates thedegree of tonal balance selected with said tone controlling means.

10. In an arrangement for selecting at will the tonal balance of anamplifier, the combination of a frame; first and second tone controlpotentiometers for controlling different ranges of the responses of saidamplifier; said potentiometers mounted on said frame with their shaftsextending toward each other; first and second thumb wheels secured tosaid first and second shafts re spectively; first and second translucentcylinders operatively associated with said first and second thumb wheelsrespectively, the first of said cylinders being coaxially disposedwithin said second cylinder; said potentiometers, thumb wheels andcylinders all having their axes coincident and parallel to the front ofsaid chassis; an electrical source of light secured within the firstsaid cylinder; means for continuously supplying electricity to saidsource during rotation of said first cylinder including a leaf springmounted on said frame and arranged to be engaged by the chassis of saidamplifier to provide electrical contact for a ground return; firstcolored means circumferentially associated with at least an axialportion of said first cylinder, the density of coloration beingdependent on the degree of rotation of said first potentiometer; secondcolored means circumferentially associated with at least an axialportion of said second cylinder, the density of coloration beingdependent on the degree of rotation of said second potentiometer; saidfirst colored means being arranged to overlap said second colored meansfor at least a portion of the axial length of said cylinders, wherebythe color of the light emerging from said portion of the axial length ofsaid cylinders, as viewed from a location fixed with respect to saidframe, will uniquely correspond to the combination of the settings ofsaid tone control potentiometers.

RUDOLPH G. MILLER. GARRARD MOUNTJOY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,528,772 Kaminski Mar. 10, 19251,740,130 Voss et a1 Dec. 17, 1929 2,334,479 Creager Nov. 16, 1943Certificate of Correction Patent No. 2,492,310

RUDOLPH G. MILLER ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Column 5, line 59, for the Word treble read bass;

and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Oflice.

Signed and sealed this 6th day of June, A. D. 1950.

December 27, 1949 THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents.

Certificate of, Correction Patent No. 2,492,310 December 27, 1949RUDOLPH G. MILLER ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Column 5, line 59, for the word treble read bass; and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Patent Office.

Signed and sealed this 6th day of June, A. D. 1950.

THOMAS F. MURPHY,

Assistant Gommz'ssioner of Patents.

